The present invention relates to an image sharing apparatus and window control method used in an computer mediated conferencing system which utilizes, e.g. work stations.
Conventional computer mediated conferencing system includes a system utilizing a work station as an image sharing apparatus shared by participants. The image sharing apparatus enables to share an image displayed in a window by all participants in an computer mediated conferencing system, i.e., a desktop conference which is held electronically by interactively connecting image sharing apparatuses via a communication network. Since the window of the image sharing apparatus is used as a white board, the apparatus is sometimes called a shared white board apparatus. The shared white board apparatus always displays the same window for all the participants of the conference, so that a drawing drawn in the window by a participant is always shared by all the participants.
In actual conference, there is often a case where a participant has a trivial question during a conference that is not important enough to interrupt progress of the conference, and the participant asks the question to a next participant. Such conversation, which takes place separately from the conference, will be referred to as a "side conversation." In the conventional desktop conference system, an image drawn on the aforementioned shared white board apparatus is displayed for all the participants of the conference. Therefore, side conversation cannot be distinguished from a conversation related to the conference. In other words, the desktop conference system is unable to satisfy the demand for side conversation.
If a participant still attempts to have a side conversation in the conventional desktop conference system, another new shared white board apparatus may be provided to be shared with a specific participant. By this, side conversation is realized without interrupting the progress of the main conference. However, there are many cases where a participant of the conference wants to have discussion while displaying the window of the shared white board used in the on-going conference in another shared white board apparatus. In such case, if side conversation takes place while viewing the white board window of the on-going conference, it becomes difficult to distinguish which is the white board window of the main conference and which is the white board window of the side conversation, thus becomes confusing. In addition, there is a problem in terms of space-efficiency, since two white boards needs to be displayed.